You may have place placed the battery the wrong way. Try to make sure that the ion battery is facing the correct direction when you put it in. You will hear a “click” sound when it is inserted correctly and now the battery should be detected.

It is possible that the mode is still on camera and if you switch it video you should be able to hear sound. If you open the screen menu you should be able to access the settings. On one of the settings you can access the volume and now you can adjust it to make it louder

A button on your camera may have become broken as a result of a fall and needs to be replaced. It is also possible that you may have been pressing the buttons too hard and they now need to be replaced.